This invention relates generally to fuel line reserve and shut off valves and more particularly concerns gravity feed reserve metering valves. Prior valves have attempted to provide reserve metering capability by providing resetable mechanisms and linkages which detect fluid level and shut off fuel flow. Vacuum feed systems have attempted to interrupt fuel flow by breaking the vacuum seal in correspondence to predetermined levels of fuel. These prior approaches have generally been bulky, complicated, and generally inapplicable to motorcycle applications where miniature size, simplicity, and extreme reliability are demanded. Further, in motorcycle applications it is highly important that a complete fuel line shut off be easily accessable and quickly operable.